The present invention relates to a vehicle-use bearing apparatus of a disk rotor in a disk brake apparatus, a hub unit to which wheels are attached, and the like. Particularly the invention relates to the vehicle-use bearing apparatus having a double row tapered roller bearing with vertex of contact angles outside of bearing.
A double row tapered roller bearing with vertex of contact angles outside of the bearing is generally used to receive large radial load, axial load and moment load which are applied from a vehicle body of large weight.
In a vehicle-use bearing apparatus having such a bearing, the bearing is externally fitted to an outer periphery of a hub wheel to which wheels are attached, and a shaft portion end of the hub wheel is deformed outwardly in a radial direction so as to be caulked to an outer end surface of one inner ring of the bearing.
In order to maintain rolling performance on rolling contact surfaces of inner and outer rings of the tapered roller, as shown in FIG. 7 which is an enlarged diagram of a main section on the caulked side of the bearing, the bearing is designed so that extended lines along rolling contact surfaces 23a and 21a of the inner ring 23 and the outer ring 21 with respect to a rotational axis L of a shaft portion of the hub wheel and an extended line along an outer peripheral surface of the tapered roller 22 meet at one point Q on the rotational axis L of the hub wheel.
In this case, θ1 is an angle of a raceway track of the inner ring 23 with respect to the rotational axis L, θ2 is an angle of a raceway track of the outer ring 21 with respect to the rotational axis L, and θ3 is an angle of an inner wall surface 23c of a cone back face rib 23b which is expanded outwardly in the radial direction on a large diameter side of the inner ring 23. The numeral 3 designates a section which is caulked by the shaft end of the hub wheel.
As to the angles of the raceway tracks θ1 and θ2 and the angle of the inner wall surface θ3, the same design is applied to the other inner ring and outer ring, not shown, and these angles correspond to the angles of the raceway tracks of the other inner and outer rings and the angle of the inner wall surface of the cone back face rib.
In the prior art, when the shaft end of the hub wheel is bent and deformed outwardly in the radial direction so as to be caulked to the outer end surface of the inner ring 23, since the rolling contact surfaces 23a and 21a of the inner and outer rings and the cone back face rib 23b are elastically deformed, the angles of the raceway tracks θ1 and θ2 and the angle of the inner wall surface 23c, θ3, which are regulated to originally required angles are occasionally changed.
In this case, a contact state of the tapered roller with the rolling contact surfaces and the inner wall surface becomes unstable, namely, a life of the bearing apparatus is influenced.